Effect of postpartum time and season on the physicochemical characteristics of Murciano‐Granadina goat colostrum

Changes in the physicochemical composition of Murciano‐Granadina goat colostrum were studied with postpartum time and season. Samples that were taken immediately after partum showed the best characteristics, with the highest concentrations of proteins, solids, urea and immunoglobulin G (IgG). Samples obtained in the spring showed the highest concentration of total IgG at all postpartum times assayed. Exhaustive statistical analysis showed that the physicochemical composition of the colostrum was greatly affected by the postpartum time and only slightly affected by the season. The high protein and total IgG concentrations make goat colostrum an interesting product for uses beyond the traditional ones.     

Local impact of renewables on employment: Assessment methodology and case study

This paper presents an integrated method that assesses the socio-economic impact of establishing renewable energy on a regional scale, in particular on the creation of jobs. The method proposed is based on the collection, critical analysis and presentation of the results obtained using primary information sources considering the jobs created as the most direct measure of the socio-economic potential of renewable energy sources. Its design includes contributions extracted from a prior analysis of the existing assessment methods, to lessen the uncertainty of the job ratios often used in these types of analysis. The integrated method implemented has been applied to the autonomous community of Aragon (Spain) as a pilot case, through which the method has been tested and the indicators selected to analyse the socio-economic impact of renewable energy sources on the jobs created, the quality of the jobs and other factors related to the socio-economic development of a territory: technological development, per capita income, territorial development and human capital.     

Evaluation and Quantification of Heat Treatments Applied to Food Preserves

The quantitative study of heat treatments for sterilisation uses the Bigelow model to calculate the sterilising value (F). Calculation of F requires the previous determination of parameters D (decimal reduction time at experimental temperature) and Z (thermal-death time parameter), obtained from the thermal-death kinetics. Herein we compare two different methods, namely the Bigelow model and a predictive-type statistical method, to calculate the sterilisation effect against Bacillus coagulans spores when heat was applied to runner bean preserves (variety: Helda). Samples were subjected to various autoclave treatments at working temperatures (T _ai) of 105, 107, 110, and 115°C for periods from 3 to 35 min. The microorganism used was B. coagulans. Sterilisation achieved by these autoclave treatments was determined by using the equation based on the Bigelow model (n _probe = F ^z _Ti/D _Ti) where n is the fractional concentration of colony-forming units (or some quality factor), F ^z _Ti is F at temperature T _i, and D _Ti is D at temperature T _i. The Bigelow model can be used to obtain Z (thermal-death time parameter), which is needed to calculate the traditional sterilisation factor F, but not to determine the reduction factor n for the heat treatments, particularly when microbial indicators with low decimal reduction times (D) are studied. The thermokinetic parameters for B. coagulans in runner bean solution resulted to be Z = 10.64°C and D ₁₂₁ = 0.0264 min (Af = 1.04). Treatment at 115°C for 20 min resulted in the most efficient sterilisation effect for B. coagulans.     

Color compensation in nitrite-reduced meat batters incorporating paprika or tomato paste

BACKGROUND: Nitrite is a key ingredient the manufacture of meat products, forming a stable pink color characteristic of cured products, retarding the development of rancidity and off‐odors and flavors during storage, and preventing microbial growth. The negative aspects of nitrite and the demands for healthy foods result in the need to reduce nitrite in cured meat products. Paprika or tomato has been employed as natural pigments in meat products. The objective of this work was to determine the effect of incorporating paprika powder or tomato paste on the texture, rancidity and instrumental and sensory color compensation in nitrite‐reduced meat batters. RESULTS: Addition of tomato paste improved moisture content, resulting in harder but less cohesive samples as compared to control and paprika‐containing meat batters. Color characteristics of reduced nitrite samples obtained higher a* red coloration (8.9 for paprika and 7.7–8.0 for tomato paste), as compared to control samples (5.65). Instrumental color was low in control samples, with high values for tomato paste and paprika samples. Nonetheless, tomato paste used to compensate color in nitrite‐reduced meat batters was ranked closer to the control sample in sensory evaluation. CONCLUSION: Color characteristics—instrumental and sensory—in these kinds of meat products were enhanced by the addition of 2.5–3.0% of tomato paste, presenting results close to the non‐reduced nitrite control. Similarly, antioxidant components of tomato paste or paprika reduced lipid oxidation. Nitrite reduction from 150 to 100 ppm could be achieved employing tomato paste as a natural pigment to improve color and texture. Copyright © 2011 Society of Chemical Industry     

Design of pH Sensors in Long-Period Fiber Gratings Using Polymeric Nanocoatings

In this paper, two different pH sensors based on the deposition of nanometric scale polymeric films onto the surface of a long-period fiber grating (LPFG) have been studied and compared. An electrostatic self-assembled (ESA) method has been used to create sensitive films with an optimal overlay thickness. Two types of sensors have been designed: The first one is based on polyallylamine hydrochloride (PAH), polyacrylic acid (PAA), and the second one was done incorporating the pigment Prussian blue (PB) in the PAH/PAA matrix. A theoretical model of multilayer cylindrical waveguides based on coupled-mode theory has been used to predict the position of the attenuation bands as a function of the overlay thickness. Both sensors were tested and compared in terms of sensitivity and response time. A faster response was obtained with the introduction of PB particles in the polymeric matrix. Linear sensors in the pH range 4-7 were obtained, showing good repeatability and high sensitivity     

Fissure analysis in one-directional slabs with on-site concrete rib by continuous formwork

This article presents a detailed analysis of a common pathology in concrete one-directional slabs with on-site rib and prefabricated concrete hollow blocks. This pathology is causing complaints from the users and tenants of the buildings affected by it pressing charges against the construction companies.This pathology consists of very thin fissures marked on the claddings, and parallel to the slab ribs. The cracks usually begin to be detected a few days after the slab is in service, after partitions and floor paving are placed and they normally appear much quicker in dry and warm weather. These fissures occur in isolation and are distanced according to the width of the slab. In addition, although the cracking lines show an apparent fixed repetition, there does not seem to be a correlation between this modulation and the frame geometry/modulation.This work analyzes the causes for this pathology type proposing some solutions to avoid it.     

An improved piecewise outer-approximation algorithm for the global optimization of MINLP models involving concave and bilinear terms

In this paper a new version of the Outer Approximation for Global Optimization Algorithm by Bergamini et al. [Bergamini, M.L., Aguirre, P., & Grossmann, I.E. (2005a). Logic based outer approximation for global optimization of synthesis of process networks. Computers and Chemical Engineering 29, 1914] is proposed, in order to speed up the convergence in nonconvex MINLP models that involve bilinear and concave terms. Bounding problems are constructed replacing these nonconvex terms by piecewise linear underestimators. These problems, which correspond to mixed-integer linear programs, are solved to generate approximate solutions with improved objective value. When no further feasible solution can be found, this guarantees that the upper bound cannot be improved in the nonconvex problem, thus providing a termination criterion. The new algorithm is applied to five different synthesis problems in the areas of water networks, heat exchanger networks and distillation sequences. The results show a significant reduction in the computational cost compared with the previous version of the algorithm.     

The Ceramide Synthase Subunit Lac1 Regulates Cell Growth and Size in Fission Yeast

Cell division produces two viable cells of a defined size. Thus, all cells require mechanisms to measure growth and trigger cell division when sufficient growth has occurred. Previous data suggest a model in which growth rate and cell size are mechanistically linked by ceramide-dependent signals in budding yeast. However, the conservation of mechanisms that govern growth control is poorly understood. In fission yeast, ceramide synthase is encoded by two genes, Lac1 and Lag1. Here, we characterize them by using a combination of genetics, microscopy, and lipid analysis. We showed that Lac1 and Lag1 co-immunoprecipitate and co-localize at the endoplasmic reticulum. However, each protein generates different species of ceramides and complex sphingolipids. We further discovered that Lac1, but not Lag1, is specifically required for proper control of cell growth and size in Schizosaccharomyces pombe. We propose that specific ceramide and sphingolipid species produced by Lac1 are required for normal control of cell growth and size in fission yeast.     

The duct selective volumetric receiver: potential for different selectivity strategies and stability issues

Recently much theoretical and experimental work has been conducted on volumetric receivers. However, not much attention has been paid to the possibilities of using different selectivity mechanisms to minimize radiation thermal losses, which are the main ones at high operating temperature. In this paper we present a duct volumetric receiver model and its results, which allow the evaluation of different selectivity strategies such as: conventional /α, geometry, frontal absorption and diffuse/specular reflection. We propose a new concept of selective volumetric receivers based on a solar-specular/infrared-diffuse radiative behaviour and evaluate its potential for efficiency improvement. In recent work on volumetric receivers based on simplified models, it has been concluded that the duct volumetric receiver is inherently unstable when working with high solar flux. We didn’t find any unstable receiver behaviour even at very high solar fluxes, and conclude that a substantial potential for efficiency improvement exists if selectivity mechanisms are properly combined.     

Synthesis and behaviour of two copolymers of poly[acrylamide-co-(N-(hydroxymethyl)acrylamide)] in ultrafiltration experiments

Summary Water absorbing materials on the basis of acrylamide copolymers have been investigated. The cross-linking of polymer chains strongly effects the degree of water absorption. The influence of starting composition of polyacrylamide : sodium hydroxide, duration of hydrolysis and irradiation conditions on cross-linking have been determined and optimized technological parameters have been derived. Water super absorbents with the ability to absorb up to 900g water by one gram material have been prepared. Received: 20 December 1999/Revised version: 19 June 2000/Accepted: 17 July 2000